Aha!
For the benefit of thread clarity, I must say I have no special information about the treatment status of those pearls - aside their appearance and label of the seller that says 'natural color'. I haven' picked them up as an example of Akoya perfection to begin with, by all means.
Terry, what shows bleaching on them?
PS. A vintage Mikimoto pin with colored pearls seemed to fit on the topic too. especially since the good pearls with natural colors are never there;
LINK to vintage color.